[Solved]-how come my android devices are not visible on my Mac?-eclipse

i know your problem is intermittent and as jim says, restarting eclipse helps when unplugging the usb and plugging it in again doesn't help. i did however find this extremely helpful detecting a new device: adb not finding my device / phone (macos x). give this a shot for your already discovered devices, to see if that helps.

sometimes adb fails to recognize devices properly. try "adb kill-server" and then "adb devices"

i had to download the android file transfer mac application, and then it worked fine. i also had to use the right usb cord -- some don't have a data channel.